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Two novel V-shaped push-pull systems based on a pyrimidine acceptor have been designed and investigated. Low-temperature measurements of the fluorescence and delayed luminescence spectra demonstrated that the emission bands of the compounds have a charge-transfer character. Despite the fact that compounds in thermal vacuum deposition films have a low fluorescence quantum yield, OLED devices based on them show high efficiency, which can be associated with the emission mechanism through delayed fluorescence. It is found that photoproducts, obtaining upon exposure to UV-irradiation of fluorophores in chloroform solution, exhibit laser activity in the red region of the spectrum.

Organic Light Emitting Dioides (OLED)devices were fabricated with blue emission based on azatrioxa[8]circulene and 4,4-N,N'-Dicarbazolyl-1,1'-biphenyl (CBP) with maximum brightness of 840 kd/m(2) at 12 V and the starting voltage of 3.5 V. The vibronic emission spectrum was analyzed by the promotive modes calculation method. The electroluminescence of fabricated OLED device is caused by the 0-0 electronic transition and single excitations of 1473 cm(-1) and 1673 cm(-1) modes and combinations thereof.

The manufacturing process of wide-band-gap matrix photodetector devices and miniaturization of their individual pixels gave rise to increased demands on the material quality and research methods. In the present paper we propose using the methods of atomic-force microscopy to study the local distribution of electrical properties of the V-defects that form in epitaxial films of HgCdTe during their growth process via molecular beam epitaxy. We demonstrate that a complex approach to studying the electrical properties of a predefined region of a V-defect allows one to obtain more detailed information on its properties. Using scanning spreading resistance microscopy, we show that, for a V-defect when the applied bias is increased, the surface area that participates in the process of charge carrier transfer also increases almost linearly. The presence of a potential barrier on the periphery of individual crystal grains that form the V-defect interferes with the flow of current and also affects the distribution of surface potential and capacitive contrast.

A series of novel D–A and D–π–A push-pull systems based on a pyrazine and quinoxaline acceptor, bearing various electron-donating triphenylamine and carbazole moieties, are compared. A significant difference in electrochemical and photophysical properties was found depending on molecular structure. The compounds have strong solvatochromic properties. Quinoxaline-containing systems exhibit delayed fluorescence (DF) in thermal vacuum deposition films. Despite the low quantum yield of fluorescence in the solid state (less than 10%), organic light-emitting diodes with sufficiently high efficiency (4.2 cd/A) have been fabricated on the basis of this push-pull systems. The best results were obtained for compounds exhibiting DF. The possible channel for increasing the efficiency of OLED can be associated with the “hot excitons” mechanism.

Numerous theoretical and experimental studies show that during epitaxial growth according to the Stranski-Krastanow mechanism in systems mismatched by the lattice constant, the change in the surface energy of the system during nucleation and further growth of quantum dots, plays the most important role. In particular, this factor determines the equilibrium and critical thicknesses of the transition from two-dimensional to three-dimensional growth, and also affects other kinetic characteristics of the ensemble of nanoclusters, including the nucleation rate, surface density, and average size of the islands. Recent theoretical studies have made it possible to determine that the surface energy in this process depends on the thickness of the material deposited on the substrate. In this paper, we construct a kinetic model of the formation and coherent growth of two-dimensional layers and quantum dots in mismatched epitaxial systems, taking into account the dependence of the specific surface energies on the thickness of the deposited material. In this approximation, we calculate the basic parameters of the formed array of nanoislands. Experimental studies were also carried out on the growth of two-dimensional layers and quantum dots of germanium on the silicon (100) surface. The results of experimental investigations confirm the proposed theoretical model.

The epitaxial growth of CdHgTe films is accompanied by the formation of V defects whose density and electronic properties greatly affect the characteristics of a terminal device based on the given material. Scanning atomic-force microscopy techniques are proposed to investigate how electronic properties vary in the V-defect region of an epitaxial CdHgTe film. It is experimentally demonstrated that variations in the component composition of individual crystallites generating V defects create not only the complex spatial distribution of a potential field but also a potential barrier along the crystallite periphery. The given barrier must alter the charge-carrier exchange between crystallites, appreciably changing the current distribution over the V-defect area.

In this paper the influence of the volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of CdHgTe (MCT) epitaxial films of p-type conductivity is investigated. Measurements of electro-physical parameters of MCT samples after irradiation have shown that a layer exhibiting n-type conductivity is formed in the near-surface area of epitaxial films. After more than 600 pulses of influence parameters and thickness of the resulting n-layer is such that the measured field dependence of Hall coefficient corresponds to the material of n-type conductivity. The obtained results show that application of volume nanosecond discharge in air at atmospheric pressure is promising for the modification of the surface properties of epitaxial films of MCT.

In this paper experimental results of research of boron ion implantation into Hg1−x Cd x Te epitaxial films of various compositions x are presented. Samples of epitaxial films were grown by the method of molecular beam epitaxy and irradiated by boron ions with the energy of 100 keV at room temperature in the range of irradiation doses 1012–1015 ions cm−2. As a result of the experimental investigations an evidence of influence of epitaxial film composition on the dynamics of accumulation and spatial distribution of electrically active radiation defects is obtained.

In this paper the local distribution of the material composition in the V-defect region of HgCdTe epitaxial films is investigated. The local composition distribution is studied by the Kelvin Force Probe Microscopy method and scanning electron microscopy with energy dispersive X-ray analysis. It is demonstrated that in the V-defect region of a Hg 1−x Cd x Te epitaxial film inhomogeneous distribution of the material component composition is observed. Analysis of the obtained experimental data shows that V-defects are distinguished by an increased mercury content.

In this work the experimental results of investigations of the dynamics of accumulation and spatial distribution of electrically active radiation defects when irradiating epitaxial films of Hg1-xCdxTe (MCT) with different material composition (x). The films, grown by molecular beam epitaxy (MBE) were irradiated by B ions at room temperature in the radiation dose range 1012 -1015 ions/cm2 and with ion energy 100 keV. The results give the differences in implantation profiles, damage accumulation and electrical properties as a function of the material composition of the films.

In this paper the influence of the volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) of p-type conductivity. It is suggested that after exposure on film surface oxide layer was formed. This layer has a built positive charge that leads to the formation of an inversion layer which "shunts" the rest of the sample so that the measured field dependence of Hall coefficient corresponds to the material of n-type of conductivity.

A pneumatic separator equipped by closed small-sized pneumatic system was developed. It ensures cleaning of seed of cereal and grain-legume crops from hard-separable impurities of different aerodynamic features after the air-sieve and trieur machines.

In the present report we studied the distribution of surface potential of the HgCdTe epitaxial films grown by molecular beam epitaxy after the impact of picosecond electron beam and volume discharge in atmospheric-pressure air. The surface potential distribution was studied by the Kelvin Force Probe Microscopy. The experimental data obtained for the variation of the contact potential difference (ΔCPD) between the V-defect and the main matrix of the epitaxial film. The investigation of the origin epitaxial films show that variation of the spatial distribution of surface potential in the V-defect region can be related to the variation of the material composition. The experimental data obtained for the irradiated samples show that the mean value of ΔCPD for the original surface differs from the one for the irradiated surface for 55 eV. At the same time the mean value of ΔCPD changes its sign indicating that the original surface of the epitaxial HgCdTe film predominantly contains the grains with increased cadmium content while after the irradiation the grains possess an increased content of mercury. Therefore, during the irradiation process a decrease of the mercury content in the near-surface region of the semiconductor takes place resulting in the alteration of the electrophysical properties in the films near-surface region. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

The purpose of this paper was investigating the effect of volume nanosecond discharge in air at atmospheric pressure on the electro-physical properties of the HgCdTe (MCT) epitaxial films grown by molecular beam epitaxy. Hall measurements of electro-physical parameters of MCT samples after irradiation have shown that there is a layer of epitaxial films exhibiting n-type conductivity that is formed in the near-surface area. After more than 600 pulses of influence parameters and thickness of the resulting n-layer is such that the measured field dependence of Hall coefficient corresponds to the material of n-type conductivity. Also it is shown that the impact of the discharge leads to significant changes in electro-physical characteristics of MIS structures. This fact is demonstrated by increase in density of positive fixed charge, change in the hysteresis type of the capacitance-voltage characteristic, an increase in density of surface states. The preliminary results show that it is possible to use such actions in the development of technologies of the controlled change in the properties of MCT. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

The thermal parameters of a SiGe microbolometer were calculated using numerical modeling. The calculated thermal conduction and thermal response time are in good agreement with the values found experimentally and range between 2x10$^-7$ and 7x10$^-8$ W/K and 1.5 and 4.5 ms, respectively. High sensitivity of microbolometer is achieved due to optimization of the thermal response time and thermal conduction by fitting the geometry of supporting heat-removing legs or by selection of a suitable material providing boundary thermal resistance higher than 8x10$^-3$ cm$^2$K/W at the SiGe interface., 11 pages, 6 figures

Integrated photoluminescence spectra of two diamond samples under laser radiation excitation at 193 and 222 nm, depending on the temperature in the range of 80-300 K and the peak intensity in the range of 7-13 MW/cm2, were investigated. At temperatures below 200 K, and the peak intensity of more than 10 MW/cm2 of laser radiation at 222 nm, the radiative recombination band of electron-hole liquid was observed in integrated photoluminescence spectra of CVD diamond sample. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Atomic-force microscopy is used to investigate the distribution of the contact-potential difference (surface potential) in Cd x Hg1 − x Te epitaxial films grown by molecular-beam epitaxy. Modification of the solid-solution composition near the V-defect results in a variation in the contact-potential difference. It is shown that the solid-solution composition varies by ∼0.05 (2.5 at %) towards increasing mercury content in the V-defect region, and a region of mercury depletion by 0.36 at % is observed at the V-defect periphery. From analysis of the surface-potential distribution, it is shown that the Cd x Hg1 − x Te epitaxial film contains unform V-defects with a diameter less than 1 μm in addition to macroscopic V-defects.

In this paper the influence of the plasma volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) films are discussed. The experimental data show that the action of pulses of nanosecond volume discharge in air at atmospheric pressure leads to changes in the electrophysical properties of MCT epitaxial films due to formation of a near-surface high- conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of MCT.

The effect of a high-frequency nanosecond volume discharge forming in an inhomogeneous electrical field at atmospheric pressure on the CdHgTe (CMT) epitaxial films is studied. The measurement of the electrophysical parameters of the CMT specimens upon irradiation shows that that the action of pulses of nanosecond volume discharge leads to changes in the electrophysical properties of CMT epitaxial films due to formation of a near-surface high-conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of CMT narrow-band solid solutions and production of structures heterogeneous with respect to conduction.

We studied the distribution of surface potential of the Hg1−xCdxTe epitaxial films grown by molecular beam epitaxy. The studies showed that the variation of the spatial distribution of surface potential in the region of the V-defect can be related to the variation of the material composition of epitaxial film. The V-defect is characterized by increased of Hg content with respect to the composition of the solid solution of Hg1−xCdxTe epitaxial film. In this paper, it was demonstrated that the unformed V-defects can be observed together with the macroscopic V-defects on the epitaxial film surface. These unformed V-defects can allow the creation of a complex surface potential distribution profile due to the redistribution of the solid solution composition.

In this paper we present the results of our research of the impact of nanosecond volume discharge on the electronic properties of the near-surface region of epitaxial Hg1−x Cd x Te films. We show that the distribution of the surface potential and, as a consequence, the material composition of the individual crystal grains that form V-defects possess a complex structure and contain regions with elevated content of both mercury and cadmium. The volume discharge treatment of the film surface leads to a decrease of the mercury content in individual crystal grains compared to the bulk of Hg1−x Cd x Te epitaxial film. This indicates a higher mercury desorption rate from the V-defect region.

In the present report we demonstrate the experimental data obtained as a result of studying the impact of nanosecond plasma volume discharge in the atmospheric-pressure air on the distribution of the surface potential in the V-defect regions of epitaxial HgCdTe films. The experimental data obtained for the variation of the contact potential difference (ΔCPD) between the V-defect and the main matrix of the epitaxial film show that the mean value of ΔCPD for the original surface differs from the one for the irradiated surface for 55 eV. At the same time the mean value of ΔCPD changes its sign indicating that the original surface of the epitaxial HgCdTe film predominantly contains the grains with increased cadmium content while after the irradiation the grains possess an increased content of mercury. Therefore, during the irradiation process a decrease of the mercury content in the near-surface region of the semiconductor takes place resulting in the alteration of the electrophysical properties in the film's near-surface region.

In this work efficiency of solar energy conversion by solar cell based on tandem structure CdZnTe/Si is analyzed. It is shown that CdTe-CdZnTe-ZnTe material system is promising for creation of high-performance cascade solar cells.

The effect of a nanosecond volume discharge forming in an inhomogeneous electrical field in various gas environments at atmospheric pressure on the CdHgTe(MCT) epitaxial films of the p-type conduction is studied. The measurement of the electrophysical parameters of the MCT specimens upon irradiation shows that a layer exhibiting the n-type conduction is formed in the near-surface region of the epitaxial films. Analysis of the preliminary results reveals that the foregoing nanosecond volume discharge in various gas environments at atmospheric pressure is promising for modification of electro-physical MCT properties.